Method for signaling in wireless communication system and apparatus supporting same

ABSTRACT

Provided is a signaling method carried out by user equipment (UE) in a wireless communication system. The method comprises: starting a prohibit timer regarding the transmission of a first UE-originated indicator; and restarting the prohibit timer when a handover indication message is received from a network.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2013/006426, filed on Jul. 18, 2013, which claims priorityunder 35 U.S.C. 119(e) to U.S. Provisional Application No. 61/672,777,filed on Jul. 18, 2012, all of which are hereby expressly incorporatedby reference into the present application.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a signaling method performed by a user equipment in awireless communication system, and an apparatus supporting the method.

Related Art

3rd generation partnership project (3GPP) long term evolution (LTE) isan improved version of a universal mobile telecommunication system(UMTS) and is introduced as the 3GPP release 8. The 3GPP LTE usesorthogonal frequency division multiple access (OFDMA) in a downlink, anduses single carrier-frequency division multiple access (SC-FDMA) in anuplink. The 3GPP LTE employs multiple input multiple output (MIMO)having up to four antennas. In recent years, there is an ongoingdiscussion on 3GPP LTE-advanced (LTE-A) that is an evolution of the 3GPPLTE.

A network may enable a transmission of a UE-originated indicationincluding UE-related information, e.g., information regarding a UEoperation environment, a service desired to be received, etc. When theUE-related information is acquired through the UE-originated indication,the network may be operated such that a UE can receive a specificservice or the UE can move on the basis of frequency and/or cellinformation provided from the UE-related information.

Although the UE-originated indication provided by the UE has theaforementioned effectiveness, a frequent transmission thereof may causean inefficient utilization of a radio resource. To avoid this, aprohibit timer may be applied so that the UE is configured not totransmit the UE-originated indication during a timer is running.Meanwhile, there is a need to consider how to handle the prohibit timerfor restricting the transmission of the UE-originated indication duringthe UE moves from one cell to another.

SUMMARY OF THE INVENTION

The present invention provides a signaling method in a wirelesscommunication system, and an apparatus supporting the method.

In an aspect, there is provided a signaling method performed by a userequipment (UE) in a wireless communication system. The method includesstarting a prohibit timer in regard to a transmission of a firstUE-originated indication and restarting the prohibit timer when ahandover indication message is received from a network.

The transmission of UE-originated indication may be restricted duringthe prohibit timer is running.

The method may further include performing a handover upon receiving thehandover indication message, wherein the restarting of the prohibittimer is performed after the handover is complete.

The method may further include transmitting a second UE-originatedindictor after the handover is complete, wherein the restarting of theprohibit timer is performed according to the second UE-originatedindication.

The transmitting of the second UE-originated indication may be performedwhen the first UE-originated indication is transmitted within a durationof 1 second prior to a time point of receiving the handover indicationmessage.

The prohibit timer may be restarted when the second UE-originatedindication indicates a normal operation.

The method may further include receiving a UE-originated indicationconfiguration, wherein the UE-originated indication configurationindicates that the UE is configured to provide the UE-originatedindication. The UE-originated indication configuration may contain aprohibit timer set value, and the started prohibit timer may be set tothe prohibit timer set value of the UE-originated indicationconfiguration.

The method may further include starting a radio resource control (RRC)connection re-establishment procedure; and stopping the prohibit timerwhen the RRC connection re-establishment procedure starts.

In another aspect, there is provided a user equipment (UE) operating ina wireless communication system. The UE comprises a radio frequency (RF)unit for transmitting and receiving a radio signal; and a processoroperatively coupled to the RF unit, wherein the processor is configuredfor starting a prohibit timer in regard to a transmission of a firstUE-originated indication; and restarting the prohibit timer when ahandover indication message is received from a network.

According to an embodiment of the present invention, a transmission of auser equipment (UE)-originated indication can be effectively controlledby running a prohibit timer. In doing so, an indiscrete transmission ofthe UE-originated indication is avoided, thereby being able to prevent awaste of radio resources. The UE-originated indication can be providedto a network and thus optimized configuration information for a UEoperation can be provided.

According to an embodiment of the present invention, a control timerwhich controls UE-originated indication signaling can be properlycontrolled during a mutual procedure between a UE and a network. Indoing so, a transmission of the UE-originated indication can be moreflexibly performed, and thus the network can effectively provideconfiguration information optimized to the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication system to which the presentinvention is applied.

FIG. 2 is a block diagram showing the structure of a wireless protocolon the user plane.

FIG. 3 is a block diagram showing the structure of a wireless protocolon the control plane.

FIG. 4 is a flowchart illustrating the operation of UE in the RRC idlestate.

FIG. 5 is a flowchart illustrating a process of establishing RRCconnection.

FIG. 6 is a flowchart illustrating an RRC connection reconfigurationprocess.

FIG. 7 is a diagram illustrating an RRC connection re-establishmentprocedure.

FIG. 8 is a flowchart illustrating a method of performing measurement.

FIG. 9 illustrates an example of a measurement configuration configuredto UE.

FIG. 10 illustrates an example in which a measurement identity isdeleted.

FIG. 11 illustrates an example in which a measurement object is deleted.

FIG. 12 shows a situation where a mutual interference can occur in anIDC environment where LTE, GPS, and BT/WiFi coexist in one UE.

FIG. 13 is a flowchart showing a UE-originated indication signalingmethod according to an embodiment of the present invention.

FIG. 14 shows an example of a UE-originated indication signaling methodaccording to an embodiment of the present invention.

FIG. 15 shows another example of a UE-originated indication signalingmethod according to an embodiment of the present invention.

FIG. 16 is a flowchart showing another example of a UE-originatedindication signaling method according to an embodiment of the presentinvention.

FIG. 17 is a block diagram showing a wireless device according to anembodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows a wireless communication system to which the presentinvention is applied. The wireless communication system may also bereferred to as an evolved-UMTS terrestrial radio access network(E-UTRAN) or a long term evolution (LTE)/LTE-A system.

The E-UTRAN includes at least one base station (BS) 20 which provides acontrol plane and a user plane to a user equipment (UE) 10. The UE 10may be fixed or mobile, and may be referred to as another terminology,such as a mobile station (MS), a user terminal (UT), a subscriberstation (SS), a mobile terminal (MT), a wireless device, etc. The BS 20is generally a fixed station that communicates with the UE 10 and may bereferred to as another terminology, such as an evolved node-B (eNB), abase transceiver system (BTS), an access point, etc.

The BSs 20 are interconnected by means of an X2 interface. The BSs 20are also connected by means of an S1 interface to an evolved packet core(EPC) 30, more specifically, to a mobility management entity (MME)through S1-MME and to a serving gateway (S-GW) through S1-U.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway(P-GW). The MME has access information of the UE or capabilityinformation of the UE, and such information is generally used formobility management of the UE. The S-GW is a gateway having an E-UTRANas an end point. The P-GW is a gateway having a PDN as an end point.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 2 is a diagram showing a wireless protocol architecture for a userplane. FIG. 3 is a diagram showing a wireless protocol architecture fora control plane. The user plane is a protocol stack for user datatransmission. The control plane is a protocol stack for control signaltransmission.

Referring to FIGS. 2 and 3, a PHY layer provides an upper layer with aninformation transfer service through a physical channel. The PHY layeris connected to a medium access control (MAC) layer which is an upperlayer of the PHY layer through a transport channel. Data is transferredbetween the MAC layer and the PHY layer through the transport channel.The transport channel is classified according to how and with whatcharacteristics data is transferred through a radio interface.

Data is moved between different PHY layers, that is, the PHY layers of atransmitter and a receiver, through a physical channel. The physicalchannel may be modulated according to an Orthogonal Frequency DivisionMultiplexing (OFDM) scheme, and use the time and frequency as radioresources.

The functions of the MAC layer include mapping between a logical channeland a transport channel and multiplexing and demultiplexing to atransport block that is provided through a physical channel on thetransport channel of a MAC Service Data Unit (SDU) that belongs to alogical channel. The MAC layer provides service to a Radio Link Control(RLC) layer through the logical channel.

The functions of the RLC layer include the concatenation, segmentation,and reassembly of an RLC SDU. In order to guarantee various types ofQuality of Service (QoS) required by a Radio Bearer (RB), the RLC layerprovides three types of operation mode: Transparent Mode (TM),Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provideserror correction through an Automatic Repeat Request (ARQ).

The RRC layer is defined only on the control plane. The RRC layer isrelated to the configuration, reconfiguration, and release of radiobearers, and is responsible for control of logical channels, transportchannels, and PHY channels. An RB means a logical route that is providedby the first layer (PHY layer) and the second layers (MAC layer, the RLClayer, and the PDCP layer) in order to transfer data between UE and anetwork.

The function of a Packet Data Convergence Protocol (PDCP) layer on theuser plane includes the transfer of user data and header compression andciphering. The function of the PDCP layer on the user plane furtherincludes the transfer and encryption/integrity protection of controlplane data.

What an RB is configured means a process of defining the characteristicsof a wireless protocol layer and channels in order to provide specificservice and configuring each detailed parameter and operating method. AnRB can be divided into two types of a Signaling RB (SRB) and a Data RB(DRB). The SRB is used as a passage through which an RRC message istransmitted on the control plane, and the DRB is used as a passagethrough which user data is transmitted on the user plane.

If RRC connection is established between the RRC layer of UE and the RRClayer of an E-UTRAN, the UE is in the RRC connected state. If not, theUE is in the RRC idle state.

A downlink transport channel through which data is transmitted from anetwork to UE includes a broadcast channel (BCH) through which systeminformation is transmitted and a downlink shared channel (SCH) throughwhich user traffic or control messages are transmitted. Traffic or acontrol message for downlink multicast or broadcast service may betransmitted through the downlink SCH, or may be transmitted through anadditional downlink multicast channel (MCH). Meanwhile, an uplinktransport channel through which data is transmitted from UE to a networkincludes a random access channel (RACH) through which an initial controlmessage is transmitted and an uplink shared channel (SCH) through whichuser traffic or control messages are transmitted.

Logical channels that are placed over the transport channel and that aremapped to the transport channel include a broadcast control channel(BCCH), a paging control channel (PCCH), a common control channel(CCCH), a multicast control channel (MCCH), and a multicast trafficchannel (MTCH).

The physical channel includes several OFDM symbols in the time domainand several subcarriers in the frequency domain. One subframe includes aplurality of OFDM symbols in the time domain. An RB is a resourcesallocation unit, and includes a plurality of OFDM symbols and aplurality of subcarriers. Furthermore, each subframe may use specificsubcarriers of specific OFDM symbols (e.g., the first OFDM symbol) ofthe corresponding subframe for a physical downlink control channel(PDCCH), that is, an L1/L2 control channel. A Transmission Time Interval(TTI) is a unit time for subframe transmission.

The RRC state of UE and an RRC connection method are described below.

The RRC state means whether or not the RRC layer of UE is logicallyconnected to the RRC layer of the E-UTRAN. A case where the RRC layer ofUE is logically connected to the RRC layer of the E-UTRAN is referred toas an RRC connected state. A case where the RRC layer of UE is notlogically connected to the RRC layer of the E-UTRAN is referred to as anRRC idle state. The E-UTRAN may check the existence of corresponding UEin the RRC connected state in each cell because the UE has RRCconnection, so the UE may be effectively controlled. In contrast, theE-UTRAN is unable to check UE in the RRC idle state, and a Core Network(CN) manages UE in the RRC idle state in each tracking area, that is,the unit of an area greater than a cell. That is, the existence ornon-existence of UE in the RRC idle state is checked only for each largearea. Accordingly, the UE needs to shift to the RRC connected state inorder to be provided with common mobile communication service, such asvoice or data.

When a user first powers UE, the UE first searches for a proper cell andremains in the RRC idle state in the corresponding cell. The UE in theRRC idle state establishes RRC connection with an E-UTRAN through an RRCconnection procedure when it is necessary to set up the RRC connection,and shifts to the RRC connected state. A case where UE in the RRC idlestate needs to set up RRC connection includes several cases. Forexample, the cases may include a need to send uplink data for a reason,such as a call attempt by a user, and to send a response message as aresponse to a paging message received from an E-UTRAN.

A Non-Access Stratum (NAS) layer placed over the RRC layer performsfunctions, such as session management and mobility management.

In the NAS layer, in order to manage the mobility of UE, two types ofstates: EPS Mobility Management-REGISTERED (EMM-REGISTERED) andEMM-DEREGISTERED are defined. The two states are applied to UE and theMME. UE is initially in the EMM-DEREGISTERED state. In order to access anetwork, the UE performs a process of registering it with thecorresponding network through an initial attach procedure. If the attachprocedure is successfully performed, the UE and the MME become theEMM-REGISTERED state.

In order to manage signaling connection between UE and the EPC, twotypes of states: an EPS Connection Management (ECM)-IDLE state and anECM-CONNECTED state are defined. The two states are applied to UE andthe MME. When the UE in the ECM-IDLE state establishes RRC connectionwith the E-UTRAN, the UE becomes the ECM-CONNECTED state. The MME in theECM-IDLE state becomes the ECM-CONNECTED state when it establishes S1connection with the E-UTRAN. When the UE is in the ECM-IDLE state, theE-UTRAN does not have information about the context of the UE.Accordingly, the UE in the ECM-IDLE state performs procedures related toUE-based mobility, such as cell selection or cell reselection, without aneed to receive a command from a network. In contrast, when the UE is inthe ECM-CONNECTED state, the mobility of the UE is managed in responseto a command from a network. If the location of the UE in the ECM-IDLEstate is different from a location known to the network, the UE informsthe network of its corresponding location through a tracking area updateprocedure.

System information is described below.

System information includes essential information that needs to be knownby UE in order for the UE to access a BS. Accordingly, the UE needs tohave received all pieces of system information before accessing the BS,and needs to always have the up-to-date system information. Furthermore,the BS periodically transmits the system information because the systeminformation is information that needs to be known by all UEs within onecell.

In accordance with Paragraph 5.2.2 of 3GPP TS 36.331 V8.7.0 (2009-09)“Radio Resource Control (RRC); Protocol specification (Release 8)”, thesystem information is classified into a Master Information Block (MIB),a Scheduling Block (SB), and a System Information Block (SIB). The MIBinforms UE of the physical configuration of a corresponding cell, forexample, a bandwidth. The SB informs UE of information about thetransmission of SIBs, for example, a transmission cycle. The SIB is aset of pieces of correlated system information. For example, a specificSIB includes only information about surrounding cells, and a specificSIB includes only information about an uplink radio channel used by UE.

In general, service that is provided to UE by a network may beclassified into three types as follows. Furthermore, the UE differentlyrecognizes the type of cell depending on what service may be provided tothe UE. In the following description, a service type is first described,and the type of cell is described.

1) Limited service: this service provides emergency calls and anEarthquake and Tsunami Warning System (ETWS), and may be provided by anacceptable cell.

2) Suitable service: this service means public service for common uses,and may be provided by a suitable cell (or a normal cell).

3) Operator service: this service means service for communicationnetwork operators. This cell may be used by only communication networkoperators, but may not be used by common users.

In relation to a service type provided by a cell, the type of cell maybe classified as follows.

1) An acceptable cell: this cell is a cell from which UE may be providedwith limited service. This cell is a cell that has not been barred froma viewpoint of corresponding UE and that satisfies the cell selectioncriterion of the UE.

2) A suitable cell: this cell is a cell from which UE may be providedwith suitable service. This cell satisfies the conditions of anacceptable cell and also satisfies additional conditions. The additionalconditions include that the suitable cell needs to belong to a PublicLand Mobile Network (PLMN) to which corresponding UE may access and thatthe suitable cell is a cell on which the execution of a tracking areaupdate procedure by the UE is not barred. If a corresponding cell is aCSG cell, the cell needs to be a cell to which UE may access as a memberof the CSG.

3) A barred cell: this cell is a cell that broadcasts informationindicative of a barred cell through system information.

4) A reserved cell: this cell is a cell that broadcasts informationindicative of a reserved cell through system information.

FIG. 4 is a flowchart illustrating the operation of UE in the RRC idlestate. FIG. 4 illustrates a procedure in which UE that is initiallypowered on experiences a cell selection process, registers it with anetwork, and then performs cell reselection if necessary.

Referring to FIG. 4, the UE selects Radio Access Technology (RAT) inwhich the UE communicates with a Public Land Mobile Network (PLMN), thatis, a network from which the UE is provided with service (S410).Information about the PLMN and the RAT may be selected by the user ofthe UE, and the information stored in a Universal Subscriber IdentityModule (USIM) may be used.

The UE selects a cell that has the greatest value and that belongs tocells having measured BS and signal intensity or quality greater than aspecific value (cell selection) (S420). In this case, the UE that ispowered off performs cell selection, which may be called initial cellselection. A cell selection procedure is described later in detail.After the cell selection, the UE receives system informationperiodically by the BS. The specific value refers to a value that isdefined in a system in order for the quality of a physical signal indata transmission/reception to be guaranteed. Accordingly, the specificvalue may differ depending on applied RAT.

If network registration is necessary, the UE performs a networkregistration procedure (S430). The UE registers its information (e.g.,an IMSI) with the network in order to receive service (e.g., paging)from the network. The UE does not register it with a network whenever itselects a cell, but registers it with a network when information aboutthe network (e.g., a Tracking Area Identity (TAI)) included in systeminformation is different from information about the network that isknown to the UE.

The UE performs cell reselection based on a service environment providedby the cell or the environment of the UE (S440). If the value of theintensity or quality of a signal measured based on a BS from which theUE is provided with service is lower than that measured based on a BS ofa neighboring cell, the UE selects a cell that belongs to other cellsand that provides better signal characteristics than the cell of the BSthat is accessed by the UE. This process is called cell reselectiondifferently from the initial cell selection of the No. 2 process. Inthis case, temporal restriction conditions are placed in order for acell to be frequently reselected in response to a change of signalcharacteristic. A cell reselection procedure is described later indetail.

FIG. 5 is a flowchart illustrating a process of establishing RRCconnection.

UE sends an RRC connection request message that requests RRC connectionto a network (S510). The network sends an RRC connection establishmentmessage as a response to the RRC connection request (S520). Afterreceiving the RRC connection establishment message, the UE enters RRCconnected mode.

The UE sends an RRC connection establishment complete message used tocheck the successful completion of the RRC connection to the network(S530).

FIG. 6 is a flowchart illustrating an RRC connection reconfigurationprocess. An RRC connection reconfiguration is used to modify RRCconnection. This is used to establish/modify/release RBs, performhandover, and set up/modify/release measurements.

A network sends an RRC connection reconfiguration message for modifyingRRC connection to UE (S610). As a response to the RRC connectionreconfiguration message, the UE sends an RRC connection reconfigurationcomplete message used to check the successful completion of the RRCconnection reconfiguration to the network (S620).

The following description relates to a public land mobile network(PLMN).

The PLMN is a network deployed and managed by a mobile network operator.Each mobile network operator manages one or more PLMNs. Each PLMN may beidentified with mobile country code (MCC) and mobile network code (MNC).PLMN information of a cell is broadcast by being included in systeminformation.

Various types of PLMNs may be considered by a UE in a PLMN selection, acell selection, and a cell re-selection.

Home PLMN (HPLMN): PLMN having MCC and MNC which are matched with MCCand MNC of UE IMSI.

Equivalent HPLMN (EHPLMN): PLMN considered as equivalence of HPLMN.

Registered PLMN (RPLMN): PLMN of which a location registration issuccessfully complete.

Equivalent PLMN (EPLMN): PLMN considered as equivalence of RPLMN.

Each mobile service consumer subscribes to the HPLMN. When a normalservice is provided to a UE by the HPLMN or the EHPLMN, the UE is not ina roaming state. On the other hand, when a service is provided to the UEby the PLMN other than the HPLMN/EHPLMN, the UE is in the roaming state,and the PLMN is called a visited PLMN (VPLMN).

When UE is initially powered on, the UE searches for available PublicLand Mobile Networks (PLMNs) and selects a proper PLMN from which the UEis able to be provided with service. The PLMN is a network that isdeployed or operated by a mobile network operator. Each mobile networkoperator operates one or more PLMNs. Each PLMN may be identified byMobile Country Code (MCC) and Mobile Network Code (MNC). Informationabout the PLMN of a cell is included in system information andbroadcasted. The UE attempts to register it with the selected PLMN. Ifregistration is successful, the selected PLMN becomes a Registered PLMN(RPLMN). The network may signalize a PLMN list to the UE. In this case,PLMNs included in the PLMN list may be considered to be PLMNs, such asRPLMNs. The UE registered with the network needs to be able to be alwaysreachable by the network. If the UE is in the ECM-CONNECTED state(identically the RRC connection state), the network recognizes that theUE is being provided with service. If the UE is in the ECM-IDLE state(identically the RRC idle state), however, the situation of the UE isnot valid in an eNB, but is stored in the MME. In such a case, only theMME is informed of the location of the UE in the ECM-IDLE state throughthe granularity of the list of Tracking Areas (TAs). A single TA isidentified by a Tracking Area Identity (TAI) formed of the identifier ofa PLMN to which the TA belongs and Tracking Area Code (TAC) thatuniquely expresses the TA within the PLMN.

Thereafter, the UE selects a cell that belongs to cells provided by theselected PLMN and that has signal quality and characteristics on whichthe UE is able to be provided with proper service.

Next, a procedure for selecting a cell by a UE is described in detail.

When the UE is powered on or camps on a cell, the UE selects/reselects acell having proper quality and performs procedures for receiving aservice.

The UE in an RRC_idle state needs to always select the cell havingproper quality and to be prepared to be receive the service through thecell. For example, the UE that has been just powered on needs to selectthe cell having proper quality so as to be registered to a network. Ifthe UE in an RRC_connected state enters the RRC_idle state, the UE needsto select a cell on which the UE camps in the RRC_idle state. As such, aprocess of selecting a cell satisfying a certain condition by the UE inorder to camp on in a service standby state such as the RRC_idle stateis called a cell selection. An important point is that the cell needs tobe selected as quickly as possible because the cell selection isperformed in a state in which the UE has not determined a cell on whichthe UE will camp in the RRC idle state. Therefore, if a cell providesradio signal quality higher than or equal to a specific reference, thecell may be selected in the cell selection process of the UE even thoughthe cell is not a cell providing best radio signal quality to the UE.

Now, with reference to the 3GPP TS 36.304 V8.5.0 (2009 March) “UserEquipment (UE) procedures in idle mode (Release 8)”, a method andprocedure for selecting a cell by a UE in 3GPP LTE are described indetail.

A cell selection process is basically divided into two types.

The first is an initial cell selection process. In this process, UE doesnot have preliminary information about a wireless channel. Accordingly,the UE searches for all wireless channels in order to find out a propercell. The UE searches for the strongest cell in each channel.Thereafter, if the UE has only to search for a suitable cell thatsatisfies a cell selection criterion, the UE selects the correspondingcell.

Next, the UE may select the cell using stored information or usinginformation broadcasted by the cell. Accordingly, cell selection may befast compared to an initial cell selection process. If the UE has onlyto search for a cell that satisfies the cell selection criterion, the UEselects the corresponding cell. If a suitable cell that satisfies thecell selection criterion is not retrieved though such a process, the UEperforms an initial cell selection process.

After the UE selects a specific cell through the cell selection process,the intensity or quality of a signal between the UE and a BS may bechanged due to a change in the mobility or wireless environment of theUE. Accordingly, if the quality of the selected cell is deteriorated,the UE may select another cell that provides better quality. If a cellis reselected as described above, the UE selects a cell that providesbetter signal quality than the currently selected cell. Such a processis called cell reselection. In general, a basic object of the cellreselection process is to select a cell that provides UE with the bestquality from a viewpoint of the quality of a radio signal.

In addition to the viewpoint of the quality of a radio signal, a networkmay determine priority corresponding to each frequency, and may informthe UE of the determined priorities. The UE that has received thepriorities preferentially takes into consideration the priorities in acell reselection process compared to a radio signal quality criterion.

As described above, there is a method of selecting or reselecting a cellaccording to the signal characteristics of a wireless environment. Inselecting a cell for reselection when a cell is reselected, thefollowing cell reselection methods may be present according to the RATand frequency characteristics of the cell.

-   -   Intra-frequency cell reselection: UE reselects a cell having the        same center frequency as that of RAT, such as a cell on which        the UE camps on.    -   Inter-frequency cell reselection: UE reselects a cell having a        different center frequency from that of RAT, such as a cell on        which the UE camps on    -   Inter-RAT cell reselection: UE reselects a cell that uses RAT        different from RAT on which the UE camps

The principle of a cell reselection process is as follows

First, UE measures the quality of a serving cell and neighbor cells forcell reselection.

Second, cell reselection is performed based on a cell reselectioncriterion. The cell reselection criterion has the followingcharacteristics in relation to the measurements of a serving cell andneighbor cells.

Intra-frequency cell reselection is basically based on ranking. Rankingis a task for defining a criterion value for evaluating cell reselectionand numbering cells using criterion values according to the size of thecriterion values. A cell having the best criterion is commonly calledthe best-ranked cell. The cell criterion value is based on the value ofa corresponding cell measured by UE, and may be a value to which afrequency offset or cell offset has been applied, if necessary.

Inter-frequency cell reselection is based on frequency priority providedby a network. UE attempts to camp on a frequency having the highestfrequency priority. A network may provide frequency priority that willbe applied by UEs within a cell in common through broadcastingsignaling, or may provide frequency-specific priority to each UE throughUE-dedicated signaling. A cell reselection priority provided throughbroadcast signaling may be called a common priority, and a cellreselection priority determined for each UE by a network may be called adedicated priority. When the dedicated priority is received, the UE mayreceive a validity time related to the dedicated priority together. Whenthe dedicated priority is received, the UE starts a validity timer whichis set to the validity time received together. The UE applies thededicated priority in an RRC_idle mode during the validity timer isrunning. When the validity timer expires, the UE discards the dedicatedpriority, and applies the common priority again.

For the inter-frequency cell reselection, the network may provide the UEwith a parameter (e.g., a frequency-specific offset) used in cellreselection for each frequency.

For the intra-frequency cell reselection or the inter-frequency cellreselection, the network may provide the UE with a neighboring cell list(NCL) used in cell reselection. The NCL includes a cell-specificparameter (e.g., a cell-specific offset) used in cell reselection.

For the intra-frequency or inter-frequency cell reselection, the networkmay provide the UE with a cell reselection black list used in cellreselection. The UE does not perform cell reselection on a cell includedin the black list.

Ranking performed in a cell reselection evaluation process is describedbelow.

A ranking criterion used to apply priority to a cell is defined as inEquation 1.R _(s) =Q _(meas,s) +Q _(hyst) , R _(n) =Q _(meas,s) −Q _(offset)

In this case, R_(s) is the ranking criterion of a serving cell, R_(n) isthe ranking criterion of a neighbor cell, Q_(meas,s) is the qualityvalue of the serving cell measured by UE, Q_(meas,n) is the qualityvalue of the neighbor cell measured by UE, Q_(hyst) is the hysteresisvalue rank n and Q_(offset) is an offset between the two cells.

In Intra-frequency, if UE receives an offset “Q_(offsets,n)” between aserving cell and a neighbor cell, Q_(offset)=Q_(offsets,n). If UE doesnot Q_(offsets,n), Q_(offset)=0.

In Inter-frequency, if UE receives an offset “Q_(offsets,n)” for acorresponding cell, Q_(offset)=Q_(offsets,n)+Q_(frequency). If UE doesnot receive “Q_(offsets,n)”, Q_(offset)=Q_(frequency).

If the ranking criterion R_(s) of a serving cell and the rankingcriterion R_(n) of a neighbor cell are changed in a similar state,ranking priority is frequency changed as a result of the change, and UEmay alternately reselect the twos. Q_(hyst) is a parameter that giveshysteresis to cell reselection so that UE is prevented from toalternately reselecting two cells.

UE measures R_(S) of a serving cell and R_(n) of a neighbor cellaccording to the above equation, considers a cell having the greatestranking criterion value to be the best-ranked cell, and reselects thecell.

In accordance with the criterion, it may be checked that the quality ofa cell is the most important criterion in cell reselection. If areselected cell is not a suitable cell, UE excludes a correspondingfrequency or a corresponding cell from the subject of cell reselection.

Radio Link Monitoring (RLM) is described below.

UE monitors downlink quality based on a cell-specific reference signalin order to detect the quality of the downlink radio link of a PCell.The UE estimates the quality of a downlink radio link in order tomonitor the quality of the downlink radio link of the PCell, andcompares the estimated quality with threshold values Qout and Qin. Thethreshold value Qout is defined as a level at which a downlink radiolink is unable to be stably received, which corresponds to a block errorrate of 10% of hypothetical PDCCH transmission by taking intoconsideration a PDFICH error. The threshold value Qin is defined as adownlink radio link quality level at which a downlink radio link is ableto be more stably received than compared to the level of Qout, whichcorresponds to a block error rate of 2% of hypothetical PDCCHtransmission by taking into consideration a PDFICH error.

A Radio Link Failure (RLF) is described below.

UE continues to perform measurements in order to maintain the quality ofa radio link with a serving cell from which the UE receives service. TheUE determines whether or not communication is impossible in a currentsituation due to the deterioration of the quality of the radio link withthe serving cell. If communication is almost impossible because thequality of the serving cell is too low, the UE determines the currentsituation to be an RLF.

If the RLF is determined, the UE abandons maintaining communication withthe current serving cell, selects a new cell through cell selection (orcell reselection) procedure, and attempts RRC connectionre-establishment with the new cell.

In the specification of 3GPP LTE, the following examples are taken ascases where normal communication is impossible.

-   -   A case where UE determines that there is a serious problem in        the quality of a downlink communication link (a case where the        quality of a PCell is determined to be low while performing RLM)        based on the radio quality measured results of the PHY layer of        the UE    -   A case where uplink transmission is problematic because a random        access procedure continues to fail in the MAC sublayer.    -   A case where uplink transmission is problematic because uplink        data transmission continues to fail in the RLC sublayer.    -   A case where handover is determined to have failed.    -   A case where a message received by UE does not pass through an        integrity check.

An RRC connection re-establishment procedure is described in more detailbelow.

FIG. 7 is a diagram illustrating an RRC connection re-establishmentprocedure.

Referring to FIG. 7, UE stops using all the radio bearers that have beenconfigured other than a Signaling Radio Bearer (SRB) #0, and initializesa variety of kinds of sublayers of an Access Stratum (AS) (S710).Furthermore, the UE configures each sublayer and the PHY layer as adefault configuration. In this process, the UE maintains the RRCconnection state.

The UE performs a cell selection procedure for performing an RRCconnection reconfiguration procedure (S720). The cell selectionprocedure of the RRC connection re-establishment procedure may beperformed in the same manner as the cell selection procedure that isperformed by the UE in the RRC idle state, although the UE maintains theRRC connection state.

After performing the cell selection procedure, the UE determines whetheror not a corresponding cell is a suitable cell by checking the systeminformation of the corresponding cell (S730). If the selected cell isdetermined to be a suitable E-UTRAN cell, the UE sends an RRC connectionre-establishment request message to the corresponding cell (S740).

Meanwhile, if the selected cell is determined to be a cell that uses RATdifferent from that of the E-UTRAN through the cell selection procedurefor performing the RRC connection re-establishment procedure, the UEstops the RRC connection re-establishment procedure and enters the RRCidle state (S750).

The UE may be implemented to finish checking whether the selected cellis a suitable cell through the cell selection procedure and thereception of the system information of the selected cell. To this end,the UE may drive a timer when the RRC connection re-establishmentprocedure is started. The timer may be stopped if it is determined thatthe UE has selected a suitable cell. If the timer expires, the UE mayconsider that the RRC connection re-establishment procedure has failed,and may enter the RRC idle state. Such a timer is hereinafter called anRLF timer. In LTE spec TS 36.331, a timer named “T311” may be used as anRLF timer. The UE may obtain the set value of the timer from the systeminformation of the serving cell.

If an RRC connection re-establishment request message is received fromthe UE and the request is accepted, a cell sends an RRC connectionre-establishment message to the UE.

The UE that has received the RRC connection re-establishment messagefrom the cell reconfigures a PDCP sublayer and an RLC sublayer with anSRB1. Furthermore, the UE calculates various key values related tosecurity setting, and reconfigures a PDCP sublayer responsible forsecurity as the newly calculated security key values. Accordingly, theSRB 1 between the UE and the cell is open, and the UE and the cell mayexchange RRC control messages. The UE completes the restart of the SRB1,and sends an RRC connection re-establishment complete message indicativeof that the RRC connection re-establishment procedure has been completedto the cell (S760).

In contrast, if the RRC connection re-establishment request message isreceived from the UE and the request is not accepted, the cell sends anRRC connection re-establishment reject message to the UE.

If the RRC connection re-establishment procedure is successfullyperformed, the cell and the UE perform an RRC connection reconfigurationprocedure. Accordingly, the UE recovers the state prior to the executionof the RRC connection re-establishment procedure, and the continuity ofservice is guaranteed to the upmost.

A report on an RLF is described below.

When an RLF occurs or a handover failure occurs, UE reports such afailure event to a network in order to support the Mobility RobustnessOptimization (MRO) of the network.

After RRC connection re-establishment, the UE may provide the RLF reportto the eNB. Wireless measurement includes in the RLF report may be usedfor a potential reason of a failure in order to identify coverageproblems. Such information may be used to borrow such events as input toother algorithms by excluding the events in MRO evaluation for anintra-LTE mobility connection failure.

If RRC connection re-establishment fails or UE does not perform RRCconnection re-establishment, the UE may be connected again in idle mode,and may generate a valid RLF report on an eNB. For such an object, theUE may store information related to the most recent RLF or handoverfailure, and may inform an LTE cell that an RLF report is valid everyRRC connection (re)establishment and handover until the RLF report isfetched by a network or for 48 hours after an RLF or handover failure isdetected.

The UE maintains the information for a state shift and a change of RAT,and indicates that the RLF report is valid again after returning back toLTE RAT.

In an RRC connection establishment procedure, the validity of an RLFreport means that UE has experienced obstruction, such as a connectionfailure, and an RLF report attributable to the failure has not yet beentransferred to a network. The RLF report from the UE includes thefollowing information.

-   -   If the last cell (in the case of an RLF) that has provided        service to the UE or the E-CGI of a target for handover has not        been known, a PCI and frequency information are used instead.    -   The E-CGI of a cell at which re-establishment has been        attempted.    -   When initializing the last handover, for example, when a message        7 (an RRC connection reconfiguration) is received by the UE, the        E-CGI of a cell that has provided service to the UE.    -   The time that has elapsed from the initialization of the last        handover to a connection failure.    -   Information indicative of whether the connection failure is        attributable to an RLF or a handover failure.    -   Wireless measurements.    -   The location of a failure.

The eNB that has received the RLF from the UE may forward the report toan eNB that had provided service to the UE prior to the reportedconnection failure. Wireless measurements included in the RLF report maybe used to identify coverage issues as a potential cause of an RLF. Suchinformation may be used to send events to other algorithm as input againby excluding the events from the MRO evaluation of an intra-LTE mobilityconnection failure.

Measurement and a measurement report are described below.

In a mobile communication system, to support the mobility of UE isessential. Accordingly, the UE continues to measure the quality of aserving cell from which the UE is now provided with service and thequality of a neighbor cell. The UE reports measured results to a networkon a proper time, and the network provides optimum mobility to the UEthrough handover, etc. In general, measurement for this purpose iscalled a Radio Resource Management (RRM) measurement.

In order to provide information that may help an operator to operate anetwork in addition to the mobility support object, UE may performmeasurement for a specific object set by the network, and may reportmeasured results thereof to the network. For example, UE receives thebroadcast information of a specific cell that has been determined by thenetwork. The UE may report the cell identity (this is also called aglobal cell identity) of the specific cell, identity information aboutthe location to which the specific cell belongs (e.g., Tracking AreaCode) and/or other pieces of cell information (e.g., whether or not itis a member of a Closed Subscriber Group (CSG) cell) to the servingcell.

If UE checks that the quality of a specific area is very poor throughmeasurement while moving, the UE may report location information andmeasured results for cells having poor quality to a network. A networkmay perform network optimization based on the reports of the measuredresults of UEs that help the operation of the network.

In a mobile communication system in which frequency reuse (frequencyreuse factor) is 1, mobility is chiefly performed between differencecells that belong to the same frequency band. Accordingly, in order towell guarantee the mobility of UE, the UE needs to well measure thequality of neighboring cells having the same center frequency as aserving cell and information about the cells. As described above, themeasurement of a cell having the same center frequency as a serving cellis called intra-frequency measurement. UE performs intra-frequencymeasurement and reports measured results thereof to a network on aproper time so that the object of corresponding measured results isachieved.

A mobile communication operator may operate a network using a pluralityof frequency bands. If the service of a communication system is providedthrough a plurality of frequency bands, in order to guarantee optimummobility for UE, the UE needs to well measure the quality of neighboringcells having center frequencies from the center frequency of a servingcell and information about the cells. As described above, themeasurement of a cell having a center frequency different from thecenter frequency of a serving cell is called inter-frequencymeasurement. UE needs to be able to perform inter-frequency measurementand to report measured results thereof to a network on a proper time.

If UE supports the measurement of a heterogeneous network, the UE maymeasure the cell of a heterogeneous network according to a BSconfiguration. The measurement of such a heterogeneous network is calledinter-Radio Access Technology (RAT) measurement. For example, RAT mayinclude an UMTS Terrestrial Radio Access Network (UTRAN) and a GSM EDGERadio Access Network (GERAN) that comply with the 3GPP standard, and mayalso include CDMA 2000 systems that comply with the 3GPP2 standard.

FIG. 8 is a flowchart illustrating a method of performing measurement.

UE receives measurement configuration information from a BS (S810). Amessage including the measurement configuration information is called ameasurement configuration message. The UE performs measurements based onthe measurement configuration information (S820). If measured resultssatisfy report conditions within the measurement configurationinformation, the UE reports the measured results to the BS (S830). Amessage including the measured results is called a measurement reportmessage.

The measurement configuration information may include the followinginformation.

(1) Measurement object information: it is information about the objecton which UE will perform measurement. A measurement object includes atleast one of an intra-frequency measurement object that is the object ofmeasurement within a cell, an inter-frequency measurement object that isthe object of measurement between cells, and an inter-RAT measurementobject that is the object of inter-RAT measurement. For example, theintra-frequency measurement object may indicate a neighboring cellhaving the same frequency band as a serving cell, the inter-frequencymeasurement object may indicate a neighboring cell having a frequencyband different form that of a serving cell, and the inter-RATmeasurement object may indicate a neighboring cell having RAT differentfrom that of a serving cell.

(2) Reporting configuration information: this is information aboutreport conditions regarding when UE reports measured results and areport type. The report conditions may include information about anevent or cycle on which the report of the measured results is triggered.The report type is information regarding that the measured results willbe configured in what type.

(3) Measurement identity information: This is information about ameasurement identity that associates a measurement object with areporting configuration so to determine when and in what type the UEwill report a specific measurement object. The measurement identityinformation may be included in a measurement report message, and mayindicate a specific measurement object for which the measurement resultis obtained and a specific reporting condition according to which themeasurement report is generated.

(4) Quantity configuration information: This is information about ameasurement unit, a reporting unit, and/or a parameter for configuringfiltering of a measurement result value.

(5) Measurement gap information: This is information about a measurementgap as a duration that can be used by the UE only for a measurementwithout consideration of data transmission with a serving cell because adownlink transmission or an uplink transmission is not scheduled.

In order to perform a measurement procedure, UE has a measurement objectlist, a measurement report configuration list, and a measurementidentity list.

In 3GPP LTE, a BS may configure only one measurement object for a singlefrequency band in relation to UE. In accordance with Paragraph 5.5.43GPP TS 36.331 V8.5.0 (2009 March) “Evolved Universal Terrestrial RadioAccess (E-UTRA) Radio Resource Control (RRC); Protocol specification(Release 8),” events that trigger measurement reports are defined in thefollowing table.

TABLE 1 Event Report Conditions Event A1 Serving becomes better thanthreshold Event A2 Serving becomes worse than threshold Event A3Neighbour becomes offset better than serving Event A4 Neighbour becomesbetter than threshold Event A5 Serving becomes worse than threshold1 andneighbour becomes better than threshold2 Event B1 Inter RAT neighbourbecomes better than threshold Event B2 Serving becomes worse thanthreshold1 and inter RAT neighbour becomes better than threshold2

If the measured results of UE satisfy a set event, the UE sends ameasurement report message to a BS.

FIG. 9 illustrates an example of a measurement configuration configuredto UE.

First, a measurement identity 1 901 connects an intra-frequencymeasurement object and a reporting configuration 1. UE performsintra-cell measurement (intra-frequency measurement), and the reportingconfiguration 1 is used to determine the criterion of a measurementresult report and a report type.

A measurement identity 2 902 is connected to the intra-frequencymeasurement object like the measurement identity 1 901, but it connectsthe intra-frequency measurement object to a reporting configuration 2.UE performs measurement, and the reporting configuration 2 is used todetermine the criterion of a measurement result report and a reporttype.

In accordance with the measurement identity 1 901 and the measurementidentity 2 902, UE sends the measured results of the intra-frequencymeasurement object although the measured results satisfy any one of thereporting configuration 1 and the reporting configuration 2.

A measurement identity 3 903 connects an inter-frequency measurementobject 1 and a reporting configuration 3. UE reports the measuredresults of the inter-frequency measurement object 1 if the measuredresults satisfy report conditions included in the reportingconfiguration 1.

A measurement identity 4 904 connects an inter-frequency measurementobject 2 and the reporting configuration 2. UE reports the measuredresults of the inter-frequency measurement object 2 if the measuredresults satisfy report conditions included in the reportingconfiguration 2.

Meanwhile, a measurement object, a reporting configuration and/or ameasurement identity may be added, changed and/or deleted. This may beindicated in such a manner that a BS sends a new measurementconfiguration message to UE or sends a measurement configuration changemessage to the UE.

FIG. 10 illustrates an example in which a measurement identity isdeleted. When a measurement identity 2 902 is deleted, the measurementof a measurement object associated with the measurement identity 2 902is stopped, and a measurement report is not transmitted. A measurementobject or a reporting configuration associated with a measurementidentity may not be changed.

FIG. 11 illustrates an example in which a measurement object is deleted.When an inter-frequency measurement object 1 is deleted, UE also deletesan associated measurement identity 3 903. The measurement of theinter-frequency measurement object 1 is stopped, and a measurementreport is not transmitted. However, a reporting configuration associatedwith the deleted inter-frequency measurement object 1 may not be changedor deleted.

When a reporting configuration is removed, UE also removes an associatedmeasurement identity. The UE stops the measurement of a measurementobject associated by the associated measurement identity. However, ameasurement object associated with a deleted reporting configuration maynot be changed or deleted.

A measurement report may include a measurement identity, the measuredquality of a serving cell, and the measured results of a neighboringcell. A measurement identity identifies a measurement object whosemeasurement report has been triggered. The measured results of aneighboring cell may include the cell identity and measured quality ofthe neighboring cell. Measured quality may include at least one ofReference Signal Received Power (RSRP) and Reference Signal ReceivedQuality (RSRQ).

Next, a multimedia broadcast and multicast service (MBMS) is describedin detail.

A transport channel for the MBMS, that is, an MCH channel, may be mappedto a logical channel, e.g., an MCCH channel or an MTCH channel. The MCCHchannel transmits an MBMS-related RRC message, and the MTCH channeltransmits a traffic of a specific MBMS service. One MCCH channel existsin every one MBMS single frequency network (MBSFN) region fortransmitting the same MBMS information/traffic. When a plurality ofMBSFN regions are provided in one cell, a UE may receive a plurality ofMCCH channels. If the MBMS-related RRC message is changed in a specificMCCH channel, a PDCCH channel transmits an MBMS radio network temporaryidentity (M-RNTI) and an indication for indicating the specific MCCHchannel. The UE which supports the MBMS may receive the M-RNTI and theMCCH indication through the PDCCH channel, may recognize that theMBMS-related RRC message is changed in the specific MCCH channel, andmay receive the specific MCCH channel. The RRC message of the MCCHchannel may be changed in each modification period, and is broadcastrepetitively in each repetition period.

The UE may receive a dedicated service during the MBMS service isprovided. For example, a certain user may use a smart phone carried bythe user to watch a TV through the MBMS service, and simultaneously mayuse the smart phone to perform chatting through an instant messaging(IM) service such as MSN or Skype. In this case, the MBMS service isprovided through an MTCH received by several UEs together, and a serviceprovided individually to each UE, such as the IM service, is providedthrough a dedicated bearer such as DCCH or DTCH.

In one region, a certain BS may use several frequencies simultaneously.In this case, in order to effectively use a radio resource, the networkmay select one of the several frequencies to provide the MBMS service atonly the selected frequency, and may provide a dedicated bearer to eachUE at all frequencies.

In this case, if a UE to which a service is provided by using thededicated beater at a frequency at which the MBMS service is notprovided intends to receive the MBMS service, the UE needs to perform ahandover to a frequency at which the MBMS is provided. For this, the UEprovides an MBMS interest indication to the BS. That is, if it isintended to receive the MBMS service, the UE transmits the MBMS interestindication to the BS. When the indication is received, the BS recognizesthat the UE intends to receive the MBMS service, and thus move the UE toa frequency at which the MBMS is provided. Herein, the MBMS interestindication implies information indicating that the UE intends to receivethe MBMS service, and additionally includes information regarding aspecific frequency to which frequency the UE intends to move.

A UE which intends to receive a specific MBMS service first recognizesbroadcast time information and frequency information used to provide thespecific service. If the MBMS service is already being broadcast or isto be broadcast soon, the UE sets a priority of a frequency at which theMBMS service is provided to a highest priority. The UE uses reconfiguredfrequency priority information to perform a cell reselection procedure,and thus moves to a cell for providing the MBMS service and receives theMBMS service.

If the UE is currently receiving the MBMS service or is interested inreceiving it and if the UE can receive the MBMS service during it campson at a frequency at which the MBMS service is provided, it can beconsidered that a top priority is applied to a corresponding frequencyduring one MBMS session in which the following cases is maintained in asituation where SIB13 is being broadcast in a reselected cell.

-   -   In a case where SIB15 of a serving cell indicates that one or        more MBMS service area identities (SAIs) are included in a user        service description (USD) of a corresponding service.    -   In a case where SIB15 is not broadcast in a serving cell and a        corresponding frequency is included in USD of a corresponding        service.

Hereinafter, in-device coexistence (IDC) will be described.

In order for a user to access various networks anytime anywhere, one UEmay be equipped with a global navigation satellite system (GNSS)receiver in addition to a transceiver for a wireless communicationsystem such as LTE, WiFi, Bluetooth (BT), etc. For example, there may bea UE equipped with LTE and BT modules to receive a VoIP service and amultimedia service by using a BT device, a UE equipped with LTE and WiFimodules for traffic distribution, a UE equipped with GNSS and LTEmodules to additionally acquire location information, etc.

In the aforementioned case, since several transceivers are located closeto each other in one UE, there may be case where transmission power ofone transmitter is greater than reception power of another receiver. Byusing a filter technique or by providing an interval in a frequency inuse, an occurrence of an IDC interference between two transceivers canbe prevented. However, when several wireless communication modulesoperate in adjacent frequencies in one UE, an interference cancellationcannot be sufficiently performed with a current filter technique. In thefuture, there is a need to solve the aforementioned problem in order fortransceivers for a plurality of wireless communication modules tocoexist in a UE.

FIG. 12 shows a situation where a mutual interference can occur in anIDC environment where LTE, GPS, and BT/WiFi coexist in one UE.

An IDC interference avoidance can be roughly classified into three typesaccording to whether there is a coordination between an LTE module andanother coexisting communication module and whether there is acoordination between the LTE module and a BS to solve an IDCinterference. A first mode is a mode in which there is no coordinationbetween the LTE module and a network for the IDC interference avoidance.In this case, since the LTE module does not know information regardinganother coexisting communication module, a service quality deteriorationcaused by the IDC interference may not be properly handled. A secondmode is a mode in which there is a coordination between coexistingcommunication modules in a UE. In this mode, an on/off state, traffictransmission state, etc., of a peer module can be known betweencoexisting modules. However, there is no coordination between the UE andthe network in this mode. A last mode is a mode in which not only acoordination between coexisting modules in the UE but also acoordination between the UE and the network exists. In this mode, thecoexisting module can know an on/off state, traffic transmission state,etc., of a peer module. In addition, the UE reports an IDC interferencestate to the network, so that the network determines to avoid the IDCinterference and takes an action for this.

The LTE module may measure the IDC interference not only through acoordination with another module in the UE as described above but alsothrough an inter/intra frequency measurement.

The interference may be the IDC interference which occurs when differentcommunication modules coexist and operate in one UE, and the IDCinterference may occur in the following coexistence situation.

The interference occurs in a situation where LTE and WiFi coexist.

The interference occurs in a situation where LTE and BT coexist.

The interference occurs in a situation where LTE and GNSS coexist.

In terms of a frequency, the communication modules operate in adjacentfrequencies as follows and thus may cause a mutual interference.

LTE TDD may operate at Band 40 (2300 MHz˜2400 MHz), and WiFi and BT mayoperate at an unlicensed band (2400 MHz˜2483.5 MHz). In this case, atransmission of LTE may cause an interference to WiFi and BT, and atransmission of WiFi or BT may cause an interference to a reception ofLTE.

LTE FDD may perform an uplink transmission at Band 7 (2500 MHz˜2700MHz), and WiFi and Bluetooth may operate at an unlicensed band (2400MHz˜2483.5 MHz). In this case, the uplink transmission of LTE may causean interference to a reception of WiFi or Bluetooth.

LTE FDD may perform an uplink transmission at Band 13 (UL: 777-787 MHz,DL: 746-756 MHz) or Band 14 (UL: 788-798 MHz, DL: 758-768 MHz), and GPSradio may perform a reception at 1575.42 MHz. In this case, the uplinktransmission of LTE may cause an interference to a reception of GPS.

At present, 3GPP considers roughly two schemes to solve the IDCinterference. A first scheme is frequency division multiplexing (FDM) inwhich an interfering communication module and an interferedcommunication module change a frequency. A second scheme is timedivision multiplexing (TDM) in which one frequency is used by coexistingcommunication modules in a time division manner.

A UE may transmit an IDC indication to a network upon sensing aninternal interference between an LTE device in the UE and another ISMband device in the UE, that is, an IDC interference. The IDC indicationmay indicate that the UE experiences the IDC interference. The IDCindication may include information regarding a specific frequency and/ora time duration pattern. Herein, the specific frequency information maybe used as a basis for performing FDM to solve the IDC interferenceproblem, and the information regarding the specific time durationpattern may be used as a basis for performing TDM. The specificfrequency information may indicate a frequency at which the IDCinterference occurs, and the specific time duration pattern informationmay indicate a time duration in which the IDC interference occurs due toan operation of another ISM band device.

Hereinafter, an enhancement diversity of data application (EDDA) and apower preference indication will be described.

Due to a diversity of a data application which is running in a UE side,an optimized configuration may be difficult in terms of UE power and UEperformance. This is because a network cannot completely recognize astate for an application which is running on the UE. To compensate forthis, a wireless communication system allows the UE to be able totransmit to the network an indication indicating a preference on a‘default’ (in terms of power saving) discontinuous reception (DRX)configuration or a “low power consumption” DRX configuration. Such anindication is called a ‘power preference indication’. The powerpreference indication may be configured to indicate whether the UEprefers a preferentially optimized configuration for the power saving.

The network may receive the power preference indication, and accordingthereto, may configure a parameter related to an operation of the UE andmay provide it to the UE. Upon receiving the power preference indicationindicating a preference on a preferentially optimized configuration forthe power saving, the network may set a long DTX to the UE or may allowthe UE to enter an IDLE state. Until the power preference indicationexplicitly indicating the preference of the preferentially optimizedconfiguration for the power saving is received, the network may operateby considering that the UE does not prefer to operate the power saving.

If a UE-originated indication such as the aforementioned IDC indication,MBMS interest indication, and power preference indication is frequentlytransmitted, an efficiency of a network operation is decreased, and aservice to be provided to the UE may deteriorate. To restrict a frequenttransmission of the UE-originated indication, a prohibit timer isproposed. The prohibit timer may specify a time at which theUE-originated indication cannot be transmitted again from a time atwhich the UE transmits the UE-originated indication. Hereinafter, asignaling method related to the UE-originated indication will bedescribed.

FIG. 13 is a flowchart showing a UE-originated indication signalingmethod according to an embodiment of the present invention.

Referring to FIG. 13, a network transmits a UE-originated indicationconfiguration to a UE (step S1310). The UE-originated indicationconfiguration may enable a transmission of the UE-originated indicationtransmission of the UE or may trigger the UE-originated indicationtransmission.

The UE-originated indication configuration may allow the UE to be ableto transmit an IDC indication and/or a power preference indication. Inthis case, the UE-originated indication configuration may be transmittedby being included in an RRC connection configuration message, an RRCconnection reconfiguration message, and/or a handover indicationmessage.

The UE-originated indication configuration is for reporting that an MBMSservice is provided, and may be for triggering the UE to transmit anMBMS interest indication. In this case, the UE-originated indicationconfiguration may be transmitted by being included in systeminformation.

The UE-originated indication configuration may include informationindicating a set value of a prohibit timer which runs when theUE-originated indication is transmitted.

The UE-originated indication configuration may be transmittedindependent of several types of UE-originated indications. For example,an IDC indication configuration for an IDC indication, a powerpreference indication configuration for a power preference indication,and an MBMS interest indication configuration for an MBMS interestindication may be transmitted by being created individually. In thiscase, the prohibit timer set value may be set individually for each typeof UE-originated indication.

The UE-originated indication configuration may be commonly transmittedfor several types of UE-originated indications. In this case, theUE-originated indication configuration may include an individualprohibit timer value based on each UE-originated indication or mayinclude a prohibit timer set value commonly applied to the several typesof UE-originated indications.

The UE transmits the UE-originated indication to the network (stepS1321), and starts and/or restarts the prohibit timer (step S1322).

If the UE-originated indication is an IDC indication, the UE maytransmit the IDC indication by including it to an IDC indicationmessage.

If the UE-originated indication is an MBMS interest indication, the UEmay transmit an MBMS interest indication by including it to an MBMSinterest indication message.

If the UE-originated indication is a power preference indication, the UEmay transmit the power preference indication by including it to a UEassistance information message. The UE interest indication may indicatewhether the UE is interested in a power saving operation or a normaloperation.

In the operation of the prohibit timer related to the transmission ofthe power preference indication, the prohibit timer may be configured tostart and/or restart by a power preference indication transmission onlyfor a case where the power preference indication indicates a preferenceon the normal operation. If the power preference indication indicates apreference on the power saving operation, the UE may not start and/orrestart the prohibit timer even if the power preference indication istransmitted.

The prohibit timer driven by the UE may be driven by being set to theprohibit timer set value included in the UE-originated indicationconfiguration. Although one prohibit timer is driven herein as anexample of a single UE-originated indication, the embodiment of thepresent invention is not limited thereto. If an individual prohibittimer is supported for each type of UE-originated indication, anindividual prohibit timer corresponding to the UE-originated indicationmay be driven.

For example, if the UE transmits the IDC indication, the UE may startand/or restart the prohibit timer for the IDC indication. Each of theindividual prohibit timers may be set to a different value.

For another example, if a common prohibit timer is set for several typesof UE-originated indications, the UE starts and/or restarts a prohibittimer which is set to the same value irrespective of a type ofUE-originated indication to be transmitted.

A time of starting/restarting the prohibit timer may be immediatelyafter the UE-originated indication is transmitted or when theUE-originated indication is transmitted, or may be before theUE-originated indication is transmitted or during a configuration fortransmitting the UE-originated indication. Although it is describedhereinafter that the prohibit timer starts/restarts in association witha transmission of the UE-originated indication, the time ofstarting/restarting the prohibit timer may be interpreted as varioustime points as described above. The time of starting/restarting theprohibit timer may be based on a UE implementation.

The UE does not transmit the UE-originated indication in a duration inwhich the prohibit timer runs (step S1331). The UE may transmit theUE-originated indication after the prohibit timer expires (step S1332).

In the method of transmitting the power preference indication related tothe running of the prohibit timer, the UE may transmit the powerpreference indication when the UE is configured to transmit the powerpreference indication but does not transmit the UE assistanceinformation message including the power preference indication. Inaddition, even after the prohibit timer expires, if the power preferenceindication is different from what is indicated by the power preferenceindication included in the recently transmitted UE assistanceinformation message, the UE may transmit the power preference indicationby including it to the UE assistance information message.

If a prohibit timer based on each type of UE-originated indication isdefined, the UE does not transmit the related UE-originated indicationonly for a case where the prohibit timer is running. On the other hand,if a prohibit timer to be commonly applied to several types ofUE-originated indications is defined, the UE may not transmit anyUE-originated indication when the prohibit timer runs.

In a situation where the UE transmits the UE-originated indication andthe prohibit timer is running, the UE may newly acquire theUE-originated indication configuration during an RRC connection-relatedprocedure and/or a handover procedure. In this case, a method ofhandling the prohibit timer which is already running may have a problem.

In addition, a network may reconfigure an operation method of a UE, orthe UE may move to a target cell through a handover or the UE mayperform an RRC connection re-establishment with the network. During theaforementioned procedure is performed and after the aforementionedprocedure is complete, there is a need to propose a detailed operationmethod of the UE in association with an operation of a prohibit timerand a transmission of a UE-originated indication.

Hereinafter, a signaling method related to a UE-originated indicationwill be described in detail according to an embodiment of the presentinvention.

1. If an RRC connection reconfiguration message including aUE-originated indication configuration is received: A UE may transmitthe UE-originated indication and may run a prohibit timer based thereon.When the UE receives the RRC connection reconfiguration message, a newUE-originated indication configuration may be included in the RRCconnection reconfiguration message. In this case, the UE may operate asfollows.

a) If the UE-originated indication configuration is acquired byreceiving the RRC connection reconfiguration message, the UE mayimmediately restart the running prohibit timer. If the newly acquiredUE-originated indication configuration includes a prohibit timer value,the UE may restart the prohibit timer by setting the prohibit timervalue to an indicated new value. If the newly acquired UE-originatedindication configuration does not include the prohibit timer value, theUE may restart the prohibit timer by setting the prohibit timer value tothe old value.

b) If the UE-originated indication configuration is acquired byreceiving the RRC connection reconfiguration message, the UE maycontinuously run the running prohibit timer. If the previously runningprohibit timer expires, the UE may newly restart the prohibit timerimmediately after the timer expires. If the newly acquired UE-originatedindication configuration includes a prohibit timer value, the UE mayrestart the prohibit timer by setting the value of the restartedprohibit timer to an indicated new value. If the newly acquiredUE-originated indication configuration does not include the prohibittimer value, the UE may restart the prohibit timer by setting the valueof the restarted prohibit timer to the old value.

c) If the UE-originated indication configuration is acquired byreceiving the RRC connection reconfiguration message, the UE may stopthe running prohibit timer.

According to the aforementioned operation of the UE, the UE may transmitthe UE-originated indication when the prohibit timer expires/stops.

2. If the UE performs a handover: If the UE performs the handover duringthe prohibit timer is running, the UE may operate as follows.

(1) If the handover indication message does not include theUE-originated indication configuration.

a) The UE may continuously run the previously running prohibit timerduring the handover is performed and even after the handover ends. TheUE may transmit the UE-originated indication when the prohibit timerexpires during the handover is performed or after the handover ends.

b) The UE may restart the prohibit timer immediately when the handoverindication message is received. The value of the prohibit timer to berestarted may be set to the old prohibit timer value.

c) The UE may stop the prohibit timer immediately when the handoverindication message is received. Further, the UE may restart the prohibittimer after the handover is complete. Even if the prohibit timer stopsduring the handover, the UE assumes that the prohibit timer is running.That is, the UE does not transmit the UE-originated indication duringthe handover.

(2) If the handover indication message includes the UE-originatedindication configuration.

a) If the UE-originated indication configuration is acquired byreceiving the handover indication message, the UE may immediatelyrestart the running prohibit timer. If the newly acquired UE-originatedindication configuration includes the prohibit timer value, the UE mayrestart the prohibit timer by setting the prohibit timer value to anindicated new value. If the newly acquired UE-originated indicationconfiguration does not include the prohibit timer value, the UE mayrestart the prohibit timer by setting the prohibit timer value to theold value.

b) If the UE-originated indication configuration is acquired byreceiving the handover indication message, the UE may continuously runthe running prohibit timer. If the previously running prohibit timerexpires, the UE may newly restart the prohibit timer immediately afterthe timer expires. If the newly acquired UE-originated indicationconfiguration includes a prohibit timer value, the UE may run theprohibit timer by setting the value of the restarted prohibit timer toan indicated new value. If the newly acquired UE-originated indicationconfiguration does not include the prohibit timer value, the UE may runthe prohibit timer by setting the value of the restarted prohibit timerto the old value.

c) If the UE-originated indication configuration is acquired byreceiving the handover indication message, the UE may stop the runningprohibit timer.

3. If an RRC connection is re-established: If the UE re-establishes theRRC connection with a network for such a reason as a radio link failure,a discussion about an operation of the UE related to a prohibit timerand a UE-originated indication transmission may be necessary.

(1) If the old prohibit timer is running.

a) The UE stops the prohibit timer immediately when the RRC connectionre-establishment procedure starts. A time of stopping the prohibit timermay be when the UE transmits an RRC connection re-establishment requestmessage to a network or a time at which the RRC connectionre-establishment message is received from the network. Even if theprohibit timer is not running, the UE does not transmit theUE-originated indication.

b) The UE continuously runs the old prohibit timer during the RRCconnection re-establishment procedure and even after the RRC connectionre-establishment procedure is complete. The UE may not transmit theUE-originated indication during the prohibit timer is running.

c) The UE may restart the prohibit timer immediately when the RRCconnection re-establishment procedure starts. A set value of theprohibit time to be restarted may be the same as a value of the oldprohibit timer. In a case where the RRC connection re-establishmentmessage is received and the prohibit timer restarts, if the prohibittimer set value is included in the RRC connection re-establishmentmessage, the prohibit timer may restart by being set to the includedvalue.

d) When the RRC connection re-establishment procedure starts, the UE maystop the running prohibit timer. If the previously running prohibittimer expires, the UE may restart the prohibit timer immediately afterthe timer expires. Even if the prohibit timer stops during the RRCconnection re-establishment procedure, the UE assumes that the prohibittimer is running. That is, the UE does not transmit the UE-originatedindication during the handover.

(2) If the prohibit timer is not running.

When the RRC connection re-establishment procedure starts, the UE maynot transmit the UE-originated indication.

Hereinafter, an embodiment of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 14 shows an example of a UE-originated indication signaling methodaccording to an embodiment of the present invention.

The example of FIG. 14 shows an example of a signaling method related toan IDC indication transmission of a UE.

Referring to FIG. 14, the UE receives an IDC indication configurationfrom a network (step S1410). The IDC indication configuration mayindicate that the IDC indication transmission of the UE is allowed. TheIDC indication configuration may include autonomous exclusion patterninformation for a low-interference operation of the UE in response tosensing of an IDC interference. The IDC indication configuration mayinclude information indicating a set value of a prohibit timer which maystart/restart when the UE transmits the IDC indication.

The UE senses that the IDC interference occurs (step S1421), andtransmits the IDC indication to the network (step S1422). Upontransmitting the IDC indication, the UE starts the prohibit timer (stepS1423). The prohibit timer may be set to a value indicated byinformation included in the IDC indication configuration.

During the prohibit timer is running, the UE receives an RRC connectionreconfiguration message including the IDC indication configuration (stepS1430). The RRC connection reconfiguration message may include the IDCindication configuration.

Even if a new IDC indication configuration is received, the UEpersistently runs the previously running prohibit timer. When the oldprohibit timer expires, the UE restarts the prohibit timer (step S1441).A value of the newly started prohibit timer may be set to the same valueas the old prohibit timer. If an IDC configuration newly acquiredthrough step S1430 includes information indicating a prohibit timer setvalue, the value of the newly started prohibit timer may be set to anindicated value. The restarted prohibit timer expires when a time basedon the set value is over (step S1441).

When the prohibit timer expires, the UE may transmit the IDC indicationto the network upon sensing the IDC interference (step S1451). The UEmay start the prohibit timer according to a transmission of the IDCindication (step S1452).

FIG. 15 shows another example of a UE-originated indication signalingmethod according to an embodiment of the present invention.

The example of FIG. 15 shows an example of a signaling method related toa power preference indication transmission of a UE.

Referring to FIG. 15, the UE receives a power preference indicationconfiguration from a network (step S1510). The power indicationconfiguration may indicate that the power indication transmission isallowed. The power preference indication configuration may includeinformation indicating a set value of a prohibit timer which maystart/restart when the UE transmits the power preference indication.

The UE transmits a UE assistance information message including the powerpreference indication (step S1521), and starts the prohibit timer (stepS1522). The UE acquires the power preference indication configuration,and the UE assistance information message may be transmitted since theUE has never transmitted a UE assistance information message includingthe power preference indication. The UE may transmit the powerpreference indication by configuring to indicate a preference on anormal operation, and may restart the prohibit timer according thereto.

The UE may perform a handover during the prohibit timer is running (stepS1530). The UE receives a handover indication message from the network(step S1531). The handover indication message may be an RRC connectionreconfiguration message including movement control information. Thehandover indication message may include a power preference indicationconfiguration.

After the handover procedure is complete, the UE transmits a UEassistance information message including the power preference indicationto the network (step S1541), and restarts the prohibit timer (stepS1542). The transmission of the UE assistance information message afterthe handover procedure may be related to a previous UE assistanceinformation message transmission time. That is, if a time at which theUE transmits the UE assistance information message in step S1521corresponds to a specific time duration prior to a time of receiving ahandover indication message, the UE may transmit the UE assistanceinformation message including the power preference indication after thehandover ends. The specific time duration may be 1 second before a timeof receiving the handover indication message.

The power preference indication of the UE assistance information messagetransmitted by the UE may indicate a preference on a normal operation.Accordingly, the prohibit timer may restart. If the power preferenceindication of the UE assistance information message transmitted by theUE indicates a preference on a power saving operation, the UE may notrestart the prohibit timer.

A value of the restarted prohibit timer may be set to the same value asthe old prohibit timer. If the power preference indication configurationnewly acquired through step S1531 includes information indicating theprohibit timer set value, the value of the restarted prohibit timer maybe set to an indicated value.

The restarted prohibit timer expires when a time based on the set valueis over (step S1550).

If the prohibit timer expires, the UE may transmit the UE assistanceinformation message including the power preference indication (stepS1560). The power preference indication may indicate a preference on anoperation scheme different from what is indicated by the powerpreference indication transmitted in step S1541. For example, if thepower preference indication transmitted in step S1541 indicates apreference on a normal operation, a power preference indicationtransmitted in step S1560 may indicate a preference on a power savingoperation. In this case, although the UE assistance information messageis transmitted in step S1560, the UE may not start/restart the prohibittimer.

FIG. 16 is a flowchart showing another example of a UE-originatedindication signaling method according to an embodiment of the presentinvention.

The example of FIG. 16 shows an example of a signaling method related toa power preference indication transmission of a UE.

Referring to FIG. 16, the UE receives a power preference indicationconfiguration from a network (step S1610). The power indicationconfiguration may indicate that the power indication transmission isallowed. The power indication configuration may include informationindicating a value of a prohibit timer which may start/restart when theUE transmits the power preference indication.

The UE transmits a UE assistance information message including the powerpreference indication (step S1621), and starts the prohibit timer (stepS1622). The UE acquires the power preference indication configuration,and the UE assistance information message may be transmitted since theUE has never transmitted a UE assistance information message includingthe power preference indication. The UE may transmit the powerpreference indication by configuring to indicate a preference on anormal operation, and may restart the prohibit timer according thereto.

During the prohibit timer is running, an RRC connection re-establishmentmay be required due to such a reason as a radio link failure. In thiscase, the UE may perform the RRC connection re-establishment procedureto recover a link with the network.

The UE starts the RRC connection re-establishment procedure bytransmitting the RRC connection re-establishment request message to thenetwork (step S1631). When the RRC connection re-establishment procedurestarts, the UE stops the running prohibit timer (step S1632). Inaddition, the UE may release a power preference indication configurationconfigured to the UE. Accordingly, a power preference indicationtransmission of the UE may be impossible when the RRC connectionre-establishment procedure starts.

Thereafter, the RRC connection re-establishment message is received fromthe network (step S1633), and the RRC connection re-establishmentcomplete message is transmitted to the network (step S1634). Therefore,the RRC connection re-establishment procedure can be complete.

In order to allow the UE to transmit the power preference indicationafter the link recovery, the network may transmit the power preferenceindication configuration. The network may transmit the RRC connectionre-establishment message by including the power preference indication sothat the indication can be transmitted immediately when the link isrecovered. When the RRC connection re-establishment procedure iscompete, the UE may start and/or restart the stopped prohibit timer.When the prohibit timer expires, the UE may transmit a UE assistanceinformation message including the power preference indication to thenetwork.

According to an embodiment of the present invention, a transmission of auser equipment (UE)-originated indication can be effectively controlledby running a prohibit timer. In doing so, an indiscrete transmission ofthe UE-originated indication is avoided, thereby being able to prevent awaste of radio resources. The UE-originated indication can be providedto a network and thus optimized configuration information for a UEoperation can be provided.

According to an embodiment of the present invention, a control timerwhich controls UE-originated indication signaling can be properlycontrolled during a mutual procedure between a UE and a network. Indoing so, a transmission of the UE-originated indication can be moreflexibly performed, and thus the network can effectively provideconfiguration information optimized to the UE.

FIG. 17 is a block diagram showing a wireless device according to anembodiment of the present invention. The device may be configured toimplement a signaling method according to the aforementioned embodimentof the present invention with reference to FIG. 13 to FIG. 16.

Referring to FIG. 17, a wireless device 1700 includes a processor 1710,a memory 1720, and a radio frequency (RF) unit 1730. The processor 1710implements the proposed functions, procedures, and/or methods. Theprocessor 1710 may be configured to control a prohibit timer accordingto an interaction with a network. The processor 1710 may be configuredto transmit a UE-originated indication to the network according towhether the prohibit timer runs. The processor 1710 may be configured toperform a UE-originated indication signaling method according to theaforementioned embodiment of the present invention with reference to thedrawings.

The RF unit 1730 coupled to the processor 1710 transmits and receives aradio signal.

The processor may include Application-Specific Integrated Circuits(ASICs), other chipsets, logic circuits, and/or data processors. Thememory may include Read-Only Memory (ROM), Random Access Memory (RAM),flash memory, memory cards, storage media and/or other storage devices.The RF unit may include a baseband circuit for processing a radiosignal. When the above-described embodiment is implemented in software,the above-described scheme may be implemented using a module (process orfunction) which performs the above function. The module may be stored inthe memory and executed by the processor. The memory may be disposed tothe processor internally or externally and connected to the processorusing a variety of well-known means.

In the above exemplary systems, although the methods have been describedon the basis of the flowcharts using a series of the steps or blocks,the present invention is not limited to the sequence of the steps, andsome of the steps may be performed at different sequences from theremaining steps or may be performed simultaneously with the remainingsteps. Furthermore, those skilled in the art will understand that thesteps shown in the flowcharts are not exclusive and may include othersteps or one or more steps of the flowcharts may be deleted withoutaffecting the scope of the present invention.

What is claimed is:
 1. A method for signaling performed by a userequipment (UE) in a wireless communication system, the methodcomprising: starting a prohibit timer related to a transmission of afirst UE-originated indication; receiving a handover indication message,which includes a timer value, from a network; performing a handoverprocedure with the received handover indication message; and restartingthe prohibit timer, wherein the prohibit timer is restarted with thereceived timer value included in the handover indication message, andwherein a transmission of another UE-originated indication is restrictedwhile the prohibit timer with the received timer value is running. 2.The method of claim 1, wherein the UE transmits a second UE-originatedindication with the restarting of the prohibit timer.
 3. The method ofclaim 2, wherein the transmission of the second UE-originated indicationis performed when the first UE-originated indication is transmittedwithin a duration of 1 second prior to a time point of receiving thehandover indication message.
 4. The method of claim 1, furthercomprising: starting a radio resource control (RRC) connectionre-establishment procedure; and stopping the prohibit timer when the RRCconnection re-establishment procedure starts.
 5. A user equipment (UE),the UE comprising: a radio frequency (RF) unit configured to transmitand receive a radio signal; and a processor operatively coupled to theRF unit, wherein the processor is configured to: start a prohibit timerrelated to a transmission of a first UE-originated indication, receive ahandover indication message, which includes a timer value, from anetwork, perform a handover procedure with the received handoverindication message, and restart the prohibit timer, wherein the prohibittimer is restarted with the received timer value included in thehandover indication message, and wherein a transmission of anotherUE-originated indication is restricted while the prohibit timer with thereceived timer value is running.
 6. The UE of claim 5, wherein theprocessor is further configured to transmit a second UE-originatedindication with restarting the prohibit timer.
 7. The UE of claim 6,wherein the transmission of the second UE-originated indication isperformed when the first UE-originated indication is transmitted withina duration of 1 second prior to a time point of receiving the handoverindication message.
 8. The UE of claim 5, wherein the processor isconfigured to: start a radio resource control (RRC) connectionre-establishment procedure, and stop the prohibit timer when the RRCconnection re-establishment procedure starts.